#!/usr/bin/env python
# -*- coding: utf-8 -*-
# @File  : p15_17.py
# @Author: huyn
# @Date  : 2018/5/3
# @Desc  :


from tkinter import *
root = Tk()

frame = Frame(root)
frame.pack(padx=10,pady=10)
v1 = StringVar()
v2 = StringVar()
v3 = StringVar()

def test(content):
    if content.isdigit():
        return True
    else:
        return False




testCMD = root.register(test)
Entry(frame,textvariable=v1,width=10,validate="key",validatecommand=(testCMD,'%P')).grid(row=0,column=0)
Label(frame,text="+").grid(row=0,column=1)
Entry(frame,textvariable=v2,width=10,validate="key",validatecommand=(testCMD,'%P')).grid(row=0,column=2)
Label(frame,text="=").grid(row=0,column=3)
Entry(frame,textvariable=v3,width=10,validate="key",validatecommand=(testCMD,'%P')).grid(row=0,column=4)


def calc():
    result = int(v1.get()) + int(v2.get())
    v3.set(result)


Button(frame,text="计算结果",command=calc).grid(row=1,column=2,pady=5)



mainloop()